Treating hydrocarbon oils with esters of phenols



v Feb. 7, 1939 o. s. PoKoRNY TREATING HYDROCARBON OILS WITH ESTERS OF' PHENOLS Filed Jan. ll, 1954 4s .monohydric phenols and inorganic Patented Feb. 7, 1939 UNITED STATES TREATTN Oldrich S. Pokorny,

signor to Standard O a corporation Application January 11,

l Claim.

relatesto a process for treating hydrocarbon oils, especially those of petroleum origin, with esters of phenols and will be fully understood from the following description 5 read in comunction w'ith the drawing, the sole ngure of which is a diagrammatic side elevation partly in section, of one form of the apparatus adapted for carrying out the invention.

Various organic. compounds have been found effective in the so-called selective solvent extraction treatment of hydrocarbon oils. Selective solvents have the property of dissolving certain constituents, mos aphthenic and aromatic nature, from the oil leaving a l5 residue which is more saturated. I haveodiscovered that esters of mono-hydric phenols and inorganic acids, such ,as ortho phosphoric and phosphorous, ortho-silicio and titanic, arsenic, antimonic and boric acids, have excellent selective properties when brought in contact with hydrocarbon oils. Only the esters of mono-hydric phenols, such as phenol, cresols, xylenols, etc., and the inorganic acids may be used directly as selective solvents. Esters of naphthols, dihydric phenols and mono alkyl esters of di-hydric phenols are either solids, melting between 140 vand 300 F., or very viscous cannot, therefore, be used in pure state. However, mixtures of these esters with. esters of mono-hydric phenols and inorganic acids, monoand di-phenyl phosphate or esters of aliphatic alcohols and mono-hydric phenols, and inor- This invention ganic acids such as ethyl-di-phenyl phosphate,

' di-ethyl-cresyl phosphate, etc., may be used. Es-

ters of phenols and organic acids may also'be used for the treatment of hydrocarbon oils, especially lubricating oils. Phenyl formate, phenyl acetate, o-cresyl acetate, xylenyl acetate, guaiacol acetate, phenyl propionate, phenyl butyrate,

40 phenyl isovalerate, and o-cresyl succinate may be mentioned as examples of such esters. Mixtures of these esters with esters of monohydric phenols and inorganic acids, monoand di-phenyl phosphate or esters of aliphatic y acids may be used. A great variety .of oils such as, for example, petroleum oils, shale oils, primaryl tars obtained by the distillation of bituminous coals, oils obtained by hydrogenatingcoals, etc., may

50 be treated by the present process. The same will be described in the following in its application to treatment of petroleum oils.

The main feature of the present process consists in agitating the oil to be treated with the 55 ester ofphenol at a temperature at which rthe esterV is liquid and at which it miscible with the oil, aliowinglayer formation togtake place-and separating the two layers. The upper layer consists of oil containing some ester go while the lower layer consists of the ester con- HYDRO STERS 0F PHENOLS Sarnia, cutan,

non-volatile syrups andalcohols, and

is notv completely,

CARBON OILS WITH Canada. il Development Company,

of Delaware 1934, Serial N0. '106.222

taining constituents dissolved fromithe oil. We will designate the former as ramnate layer or phase and the latter as extract layer or phase. Both layers are then furtherY treated for the separation of the oil and the ester.

Since the esters of phenols and inorganic compounds which are used as selective solvents in the present invention are high boiling compounds, their separation from the oil requires a dierent method, according to whether a lighter or a heavier oil is treated. Thus, for example, trio-cresyl phosphate has a boiling point of about 400 C. (752 F.) while triphenyl phosphate has a boiling point of about 410 C. (770 F.). Tetrao-cresyl ortho-silicate has a boiling point of u about 438 C. (820 FJ.' while tetra-xylenyl ortho silicate has a boiling point of about 455 C. (850 F.) Tri-cresyi arsenite has a boiling point above 360 C. (680 F.) at a reduced pressure of 30 mm. of mercury (1.18 inches). I have foun light hydrocarbons such as those usually occurring in naphtha and kerosene, and even in gas oil, can be very advantageously separated from said esters by distilling of! the hydrocarbons under atmospheric or reduced pressure. It is, however, not feasible to separate oils in the lubricating oil range from such esters by distillation and it is necessary to resort to other methods of. separation. I found that it is feasible to remove the esters from such heavy oils by washing with 93% etirvl alcohol and then separating the alcohol by distillation. isopropyl a1- cohol, acetone, very light hydrocarbons such as butaneor propane fractions, etc., may also be used in the washing operation.

'As stated above. the present invention allows the separation of an oil into constituents of unsaturated and aromatic nature which are soluble in the esters and into more saturated constituents which remain insoluble at the treating temperature. When this process is applied to naphthas, it is found that the part soluble in the ester has av higher octane number than the insoluble part. One aspect of the present invention relates to the improvement by cracking of the low octane number ester-insoluble part of the naphtha. The cracking of such naphtha improvesA its anti-knock qualities and the naphtha obtained by the cracking is then blended with the one obtained asv extract. The treating may be lcarried out either in one or several 'batch operations or in continuous method. 'I'he principle of the countercurrent treatment is preferably Referring now to the figure, same will be described in connection with the methodof operation. Number l designates a tank for the oil to be treated, and 2 a tank for the treating agent, viz. the phenol ester. The oil and the ester are admitted into the treater 3 from which the 60 d that l Y 48.4 A. P. I., a refractive and an aniline point of 147.8

yield of 77% by volume aniline point of 156.1 F., with 23% raffinate phase and the extract'phase are separately removed into containers 4 and 5 respectively. The remaining part of the iigure shows the separation of the treating agent from the two phases by means of distillation, as in the case of treating naphthas, kerosenes and gas oils.

'I'he two phases are passed through heating coils 6 and 1 into the stripping towers 8 and 9 respectively, in which evaporation takes place. The unvaporized treating agent is removed from the towers through coolers I0 and I I into the storage tank 2. 'I'he refined oil which leaves tower 8 through the overhead vapor line is condensed in condenser I2 and then pumped into the refined oil tank I3'. Similarly, the extract which leaves tower 9 through the overhead vapor line is condensed in condenser I4 to the extract tank I5. The distillation may be carried out under atmospheric pressure or under vacuum.

The following examples will illustrate the present invention: A naphtha of Mid-Continent o-rigin of 52.2 A. P. I. gravity boiling between 230 and 400 F., having an aniline point of 133 F., a refractive index at 20 C. of 1.4276 and an octane number of 41 is treated with 50% its volume of tri-o-cresyl phosphate at a temperature of 10-12 F. 14.0% by volume of the naphtha is recovered from the solvent phase while 86.0% by volume is recovered from the naphth" phase. In both cases the hydrocarbons were sei arated from the solvent by means of distillation. The oil recovered from the solvent phase had a gravity of index at 20 C. of 1.4380, an aniline point of 108 F. and an octane number of 53.4, while the corresponding values for the oil recovered from the naphtha phase were 52.9 A.,P. I., 1.4260, 136.7 F. and 34.

Treating the same naphtha with triphenyl phosphate at F. led to analogous results.

A refined oil (kerosene) which has been finished by an alkali anddoctor treatment followed by water washing having a gravity of 42.1 A. P. I. boiling within 350-530 F., with a ring number of42, a refractive index at 20 C. of 1.4521 F., was treated with two 50% by volume batches of tri-o-cresyl phosphate at 47-48 F. A yield of 70% by volurne was obtained from the refined oil phase and a yield of 14 and 16% by volume from the first and second solvent phases. from the refined oil phase had a gravity of 44.6 A. P. I., ring number of 68, refractive index at 20 C. of 1.4451 and an aniline point of 158.2 F., while the oils recovered from the rst and-sec batches of solvent had a gravity of 38.7 and 40.3, ring number of 9 and 26, refractive index of 1.4647 and 1.4584 and an aniline point of 120.9 and F. respectively. The ring number is compounded from viscosity oil and is an index which indicates the burning quality of kerosene. High ring number indicates good burning quality. It is therefore seen that' the treatment 'with esters of phenols irnproves the gravity and the burning quality of the oil.

Treating the same rened oil with one batch of 100% by volume of triphenyl phosphate, a

was obtained, with a gravity of 43.9 A. P. I., ring number 61, refractive index 1.4470, and of extract.

The inspection of the. extract gave a gravity of l38.3 A. P. I., ring member 5, refractive index 1.4646 and aniline point of 1 21.2 F.

and then pumpedi Saybolt Universal at 100 The oil recovered' and gravity of thev of improvedrened oil In both the treatment of naphtha and the rened oils the boiling range of the rened product and of the extract were very nearly the same as the boiling range of the original raw material.

'I'he following example will illustrate the treatment of lubricating oilszf'A Colombian flash coil distillate of viscosity 101 seconds Saybolt Universal at 210 F. and a viscosity index of 23 was treated in a single batch operation with triortho-cresyl phosphate at F. 'I'he railnate was Washed with four 75% batches of 93% ethyl alcohol to remove the tri-cresyl phosphate and the alcohol was then stripped under reduced pressure. The yield of solvent free raflinate was 85.8% by volume of the charge, and had a viscosity of 1735 seconds Saybolt Universal at 100 F. and 93 seconds at 210 F. and a viscosity index of 45.

Two 100% treats at 160 F. followed by an alcohol wash as above stated resulted in a 41% yield of rainate with a viscosity of 890 seconds F., 81 seconds at 210 F. and a viscosity index of 92. The viscosity index is determined by the method described in the article of E. W. Dean appeared in the Chemical and Metallurgical Engineering Journal, vol. 36, No. 10, October 1929. Viscosity index of 100 designates good grade Pennsylvania lubricating oils while a lower viscosity index designates a poorer lubricating oil. 'Ihe above gures therefore illustrate that very considerable improvement is obtained by the treatment of lubricating stocks with esters of phenols.

Instead of treating the lubricating oils with pure esters, mixtures of such esters may be used, or mixtures of esters with various organic solvents such as aliphatic alcohols, acetone, phenol, cresols, xylenols, and alkyl ethers of phenols.

In the follow' g claims the expression ester of a phenol an inorganic or organic acid and a monoor poly-hydric phenol or their homologues, including the ortho, meta and para derivatives, or an ester of an acid and a' hydroxy compound of a poly-cyclic aromatic hydrocarbon. In case of poly-basic acid, one or more of the acid hydroxyl groups may be combined with a phenol and some of the other hydroxyl groups may also be combined with an alcohol.

Various modifications of the present process will be apparent to those familiar with the art, and therefore the invention is not to be limited by the examples given for illustration, but only by the following claim in vwhich it is my intention to claim all novelty inherent to the invention.

What I claim is:

The process of treating a petroleum oil belonging to naphtha and burning oil range and composed mainly of parailnic, naphthenic and aromatic compounds,- which comprises agitating the oil with a sufficient amount of tri-phenyl phosphate, said tri-phenyl phosphate having a boiling paint higher than about 752 F. and having a preferential solvent action for the naphthenic and aromatic constituents of the petroleum oil to cause a formation of two layers of liquid, allowing the formation of a raflnate layer and an extract layer to take place at a temperature'below that at which the selective solvent becomes completely miscible with the oil, separating the two layers, and separately recovering oil sub,-y stantially free of .the selective solvent from the layers by means of distillation.

and G. H. B. Davis which 

